1. Field of the Invention
The present invention relates to a passenger conveyer, and in particular to a driving pulley which drives a hand rail and more particular to a driving pulley which is capable of controlling a moving speed of a hand rail.
2. Description of Related Art
Generally, a passenger conveyer is installed in an airport, subway, building, etc. and is an apparatus for effectively conveying passengers from a position to another position. As examples of a passenger conveyer, an escalator is known for conveying passengers from one position to another position at a different height, or a moving walkway for conveying passengers horizontally from one position to another position.
The above-described passenger conveyer includes a plurality of steps on which a passenger steps, a pair of balustrades each of which are installed uprightly and continuously near each side of the steps from a boarding position to a taking-off position, hand rails movably installed on the balustrade and moving along a predetermined loop, and a driving apparatus for driving the steps and the hand rails.
The conventional passenger conveyer will be explained with reference to the escalator.
First, FIG. 1 is a schematic lateral cross-sectional view illustrating a conventional escalator. As shown therein, reference numeral 11 represents a plurality of steps 11 on which passengers stand. The steps 11 are connected with a step chain 44 and move along a predetermined loop depending on a driving operation of the step chain 44. The connection of the steps 11 and the step chain 44 will be explained in more detail with reference to FIGS. 2A and 2B.
A pair of balustrades 21 are installed uprightly and continuously near side edges of the steps, from the boarding position of the passengers to the stepping-off position of the passengers for providing a lateral boundary of the passenger conveyor. A hand rail guide(not shown) is fixedly installed at each upper surface of the balustrades 21.
The hand rail 20 is guided by the hand rail guide and surrounds the balustrades 21. Reference numeral 32A is a transmission output sprocket connected with an output shaft of the transmission which increase the rotation driving torque of a driving motor(not shown). The transmission output sprocket 32A, and the connection and driving force transfer structure of the transmission and the motor will be explained with reference to FIGS. 3A and 3B.
The transmission output sprocket 32A is driven by a pair of step driving sprockets 42a and 42b via driving chain 33.
The step driving sprockets 42a and 42b are connected with pair of step driven sprockets 46a and 46b installed below the lower balustrades 21 of the escalator. The step driving sprockets 42a and 42b are drivingly connected with a hand rail driving pulley 60 through a driving force transfer chain(not shown).
A part of the loop of the hand rail 20 is wound on the driving pulley 60 and is moved by the rotation of the hand rail driving pulley 60.
The operation of the conventional escalator will be explained.
When rotating the motor shaft by supplying power to the motor, the transmission connected with the output shaft of the motor increases or decreases the driving torque of the motor by using the gears installed therein. The transmission output sprocket 32A connected with the output shaft of the transmission is rotated, and the rotation force of the transmission sprocket 32A is transferred to the step driving sprockets 42a and 42b through the driving chain 33. Therefore, the step driving sprockets 42a and 42b are rotated, and the step chain 44 and the step driven sprockets 46a and 46b connected with the step driving sprockets 42a and 42b are rotated. The steps 11 connected with the step chain 44 are moved upwardly or downwardly. Since the hand rail driving pulley 60 is connected with the step driving sprockets 42a and 42b, when the step driving sprockets 42a and 42b are rotated, the hand rail driving pulley 60 is rotated thereby moving the hand rail 20. As a result, when passenger boards on the step 11, the passenger is conveyed upwardly or downwardly with his hands holding the hand rail 20.
FIGS. 2A and 2B are front and lateral views illustrating a connection between the step 11 and the step chain 44.
As shown therein, the step 11 includes a pair of horizontally extending front wheel roller rotation shafts 11c passing through the step chain 44 from a predetermined position of the upper sides of the step 11, and a pair of horizontally extending rear wheel roller rotation shafts 11d from lower sides of the step.
A pair of front wheel rollers 11a are rotatably installed on the front wheel roller rotation shafts 11c, and a pair of rear wheel rollers 11b are rotatably installed on the rear wheel roller rotation shafts 11d. Therefore, when the step chain 44 rotates, since the front wheel roller rotation shafts 11c are connected with the step chain 44, the step 11 moves in the same direction as the step chain 44.
FIG. 3A is a schematic perspective view illustrating a step and a driving unit which drives the step, and FIG. 3B is a plan view illustrating a driving connection relationship between a driving unit and a hand rail driving unit of FIG. 3A.
As shown therein, the motor 31 is connected with the transmission 32. A plurality of transmission gears(not shown) of transmission 32 are connected with an output shaft of the motor 31, so that the rotation torque from the output shaft of the motor 31 is increased and the rotation velocity of the output shaft is decreased.
The transmission output sprocket 32a is connected with an output of the transmission 32 and is rotated by the rotation torque from the transmission 32.
The main sprocket 43 is drivingly connected with the transmission output sprocket 32a through the driving chain 33.
Therefore, when the transmission output sprocket 32a is rotated, rotation torque is transferred to the main sprocket 43 through the driving chain 33 for rotating the main sprocket 43. The main sprocket 43, the step driving sprockets 42a and 42b and one hand rail driving sprocket 52 are coaxially connected with the main driving shaft 41, so that they are all rotated together with the main driving shaft 41. The main driving shaft 41 is supported by a support and rotates as the main sprocket 43 rotates. The hand rail driving sprocket 52 is drivingly connected with the hand rail driven sprocket 53 through the hand rail chain 54. Therefore, when the hand rail driving sprocket 52 is rotated, the rotation torque is transferred to the hand rail driven sprocket 53. The hand rail driven sprocket 53 is rotatably engaged to the hand rail driving shaft 51, and a pair of hand rail driving pulleys 60 are coaxially engaged to the hand rail driving shaft 51.
Therefore, when the motor 31 is rotated, the rotation torque of the motor is increased or decreased by the transmission for rotating the transmission output sprocket 32a. The rotation torque of the transmission output sprocket 32a is transferred to the main sprocket 43 through the driving chain 33 for rotating the main sprocket 43. The rotation torque of the main sprocket 43 is transferred to a pair of the step driving sprockets 42a and 42b and one hand rail driving sprocket 52 through the main driving shaft 41.
Therefore, as the step chain 44 rotates, the step 11 is moved upwardly or downwardly, so that passengers are moved to a predetermined floor or destination. When the hand rail driving sprocket 52 is rotated, the rotation torque is transferred to the hand rail driven sprocket 53 through the hand rail chain 54 for rotating the hand rail driven sprocket 53.
Therefore, the hand rail driving pulleys 60 coaxially connected with the hand rail driven sprocket 53 and the hand rail driving shaft 51 are rotated thereby rotating the hand rail 20.
The driving connection relationship between the hand rail driving pulley 60 and the hand rail 20 will be explained in detail with reference to FIG. 4.
The transmission output sprocket 32a is drivingly connected with the main sprocket 43 through the driving chain 33. The hand rail driving sprocket 52 is coaxially connected with the main sprocket 43. The hand rail driving sprocket 52 is drivingly connected with the hand rail driven sprocket 53 through the hand rail chain 54. A first tension compensating roller 54a is installed at an upper location between the hand rail driving sprocket 52 and the hand rail driven sprocket 53 for compensating the tension of the hand rail chain 54. As a result, the hand rail chain 54, which receives a driving force from the hand rail driving sprocket 52 moves to the hand rail driven sprocket 53 through the tension compensating roller 54a in a state that the tension is tightly compensated. The second tension compensating roller 20a is installed at a location between the hand rail driving pulley 60 and the balustrades 21 for tightly compensating the tension of the hand rail 20. Reference numerals 62a and 62b represent pressure belt rollers which support the pressure belt 63 which is installed to contact the hand rail 20 below the hand rail driving pulley 60 so as to increase a friction force between the hand rail driving pulley 60 and the hand rail 20. Therefore, the rotation torque from the transmission output sprocket 32a is transferred to the main sprocket 43 through the driving chain 33, so that when the main sprocket 43 is rotated, the hand rail driving sprocket 52 coaxially connected with the main sprocket 43 is rotated. The rotation torque of the hand rail driving sprocket 52 is transferred to the hand rail driven sprocket 53 through the hand rail chain 54 in a state that the tension is compensated by the first tension force control roller 54a. When the hand rail driven sprocket 53 is rotated, the driving pulley 60 coaxially connected with the sprocket 53 is rotated therefore, the hand rail 20 closely contacts with the driving pulley 60 by a pressure of the pressurizing belt 63 and rotates along the balustrades 21 by a friction force with the driving pulley 60.
The construction and operation of the conventional hand rail driving pulley unit, hand rail and pressurizing belt will be explained with reference to FIGS. 5A and 5B.
The conventional hand rail driving pulley unit includes a hand rail driving shaft 51. A boss portion 60a has a through hole into which the hand rail driving shaft 51 is inserted. A spoke member 60 has three spoke portions 60b extending radially extended from the boss portion 60a. A main wheel 66 has a flange portion 66. Three support members 64, (namely, engaging members), engage for engaging the main wheel 66 and the spoke members 60. A bolt 65a supports the head portion to the support member 64 and passes through the main wheel 66 and the spoke member 60. A nut 65b is engaged with the threaded portion of the bolt inserted through the main wheel 66 and the spoke member 60. A ring-shaped elastic friction member 61 is adhered on the outer circumferential surface of the main wheel 66.
As shown in FIG. 5A, the main wheel 66 is ring-shaped, and as shown in FIG. 5B, the lateral cross-section of the same is L-shaped. The main wheel 66 includes three bolt insertion holes each of which formed at about an angle of 120 degrees so that the bolts 65a are inserted thereinto. The main wheel 66 is preferably made of a metallic material having a good mechanical strength. The support member 64 is used in order to increase the mechanical durability of the main wheel 66 which may be decreased because of the holes of the bolt insertion holes after the spoke member 60 is connected with the main wheel 66 using the bolt 60a and the nut 60b. The spoke member 60 is used for drivingly coupling the hand rail driving shaft 51 to the main wheel 66. One hole in which the bolt 60a is inserted is formed at a portion contacting the main wheel 66 among the spokes. Therefore, the bolt which passes through a center hole among three bolts inserted into one support member 64 passes through the main wheel 66 and the spoke member 60. The remaining two bolts only pass through the main wheel 66. The hand rail driving pulley unit frictionally contacts the hand rail 20 for moving the hand rail 20, so that the friction member 61 is formed by winding a band formed of an elastic resin material such as rubber onto an outer circumferential surface of the main wheel 66. The upper surface of the friction member 61 which contacts the outer circumferential surface of the main wheel 66 is flat in order to increase a bonding force with the outer surface of the main wheel 6. In addition, the outer surface of the main wheel 66 is flat in order to implement a full contact with the friction member 61.
The pressure belt 63 is positioned higher than the portion of the friction member 61 in which the belt surface contacts with the hand rail 20 in order to increase the contact area of the hand rail 20 contacting with the friction member 61, so that as shown in FIG. 5A, the pressure belt 63 is downwardly deflected by the hand rail driving pulley unit.
In this state, an elastic restoring force of the upper surface of the pressure belt 63 is applied to upwardly press the hand rail 20 between the pressure belt 63 and the friction member 61. Therefore, the hand rail 20 closely contacts with the friction member 61. The pressure belt 63 is supported by the belt rollers 62a and 62b which maintain tension in the pressure belt 63. The pressure belt 63 reciprocates between the belt rollers 62a and 62b by the friction force of the hand rail 20 when the hand rail 20 is moved by the rotation of the friction member 61.
The operation of the conventional hand rail driving pulley unit will be explained.
When the driving force is applied through the hand rail chain 54, and the hand rail driven sprocket 53 is rotated, the spoke member 60b drivingly connected with the hand rail driven sprocket 53 through the hand rail driving shaft 51 is rotated.
Therefore, the main wheel 66 connected with the spoke member 60b by the engaging member is rotated, and the friction member 61 fixed to the outer surface of the main wheel 66 is rotated. The hand rail 20 is rotated along the frames by the friction with the friction member 61 which is rotated by the pressure from the pressure belt 63.
In the thusly constituted conventional passenger conveyer, it is very important to move the step 11 and the hand rail 20 at a same speed so that safety of the passengers may be protected.
The motor 31, the transmission 32, the driving force transfer driving chain 33, and the main driving shaft 41 are used as a common driving unit for driving the step 11 and the hand rail 20 at the same speed. Furthermore, the diameters of the hand rail driving sprocket 52 and the hand rail driven sprocket 53 are same and the driving operation of the same is implemented by the chain 54. The hand rail 20 is driven by the main wheel 66 which is coaxially connected with the hand rail driven sprocket 53.
By above mentioned construction, the step 11 and the hand rail 20 may be moved at the same speed.
However, the friction member 62 and the hand rail 20 may wear down over time, so the friction force between the friction member 61 and the hand rail 20 decreases. Therefore, a speed difference occurs between the moving speeds of the step 11 and the hand rail 20. In particular, since the circumference of the friction member 61 is very short relative to the entire length of the hand rail 20, wearing down of the friction member 61 may occur quickly compared to wearing down of the hand rail 20. Thus, moving speed difference between the step 11 and the hand rail 20 is mainly due to the wear of the friction member 61.
However, in the conventional passenger conveyer, since the wear of the friction member is not compensated for, in order to compensate for the resultant speed difference, the worn-down friction member 61 must be removed from the main wheel 60 and replaced with a new friction member bonded on an outer surface of the main wheel 60 to compensate the speed difference. In addition, there no other way for overcoming the speed difference problem except for substituting a new hand rail when the old hand rail is worn.